Add choice of ISO image to use when multiple images are found on the installation medium (?DebianBug: 564441). This includes a full rewrite of the state machine in the iso-scan component. This work was contributed by Frans Pop and Frédéric Boiteux

Translations:

New language supported: Uyghur

Behavioral changes in this release

Make sure to put "hda" into the ?CoLo config file instead of "sda" since ?CoLo only knows about the former. (614839)

Remove 5 second sleeps when debootstrap finds additional required dependencies. d-i just got that much faster.